The alliance would have been unstable, not only because of Wilhelm II, but also due to conflicting economic interests between Britain and Germany.
It would have isolated and antagonised France.
Increased French commitment in the Balkans?
If, however, an integration even into switching alliances would have prevented Germany`s isolation, then the World War I would, if it occurs, certainly not occur as IOTL. If Serbia only had French and Russian protection, it´s doubtful whether Austria-Hungary`s violation of Serbian independence would really drag France and Russia into a war they cannot win. (OTOH, it did drag Germany and Austria-Hungary into one they could not win IOTL. Hm.)